1 . Used to indicate the place, person, or thing that someone or something moves toward, or the direction of something. Example : I am heading to the entrance of the building.
2. Used to indicate a limit or an ending point. Example : The snow was piled up to the roof.
3. Used to indicate relationship. Example : This letter is very important to your admission.
4. Used to indicate a time or a period. Example : I work nine to six, Monday to Friday.